# Explain why a gene can be used as a set of instructions to make a specific protein.

> AQA A-Level Biology (7402) — 3.1.5 Nucleic Acids · Explain · 5 marks

> Genes are sections of DNA found in the nucleus of cells. Each gene codes for a specific protein that the cell needs to function.

## Mark scheme (5 marks)

1. A gene is a section of DNA / made of bases
2. The sequence of bases in a gene codes for the sequence of amino acids in a protein
3. Each set of three bases (triplet / codon) codes for a specific amino acid
4. The sequence of amino acids determines the structure / shape of the protein
5. Different genes have different base sequences, so code for different proteins / each gene codes for a unique protein

## Key terms

- [gene](https://www.gradenine.co.uk/glossary/gene)
- [protein](https://www.gradenine.co.uk/glossary/protein)

## Related

- [Revision notes for AQA A-Level Biology (7402)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-a-gene-can-be-35be9c23) · Published by Druglandscape Ltd.